Java web错误汇总

环境：

• 电脑：win 10

• IDE：

• • Eclipse Java EE IDE for Web Developers.
• • Version: Luna Service Release 2 (4.4.2)
• • Build id: 20150219-0600

1、properties读取配置文件，报空指针异常错误

• 错误信息：

java.lang.NullPointerException
	at java.util.Properties$LineReader.readLine(Properties.java:434)
	at java.util.Properties.load0(Properties.java:353)
	at java.util.Properties.load(Properties.java:341)
	at com.javasm.util.JdbcUtils.getConnection(JdbcUtils.java:20)
	at com.javasm.util.JdbcUtils.tetsConnection(JdbcUtils.java:37)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

• 源码：

InputStream inputStream = JdbcUtils.class.getClassLoader()
				.getResourceAsStream("dbconfig.properties");
		Properties properties = new Properties();

• 原因：配置文件路径书写错误！！！

• 修改后的路径：

InputStream inputStream = JdbcUtils.class.getClassLoader()
				.getResourceAsStream("com/javasm/util/dbconfig.properties");
		Properties properties = new Properties();

• 注意：配置文件直接放在项目根目录下 无法正确读取，只有放在对应的目录下才可以